31x+77=15(x+1)²
31x+77=15(x²+2x+1)
31x+77=15x²+30x+15
15x²+30x+15-31x-77=0
15x²-x-62=0
D=1-4*15*(-62)=3721
x1,2=
x1=
x2=
31x+77=15(x+1)²
31x+77=15(x²+2x+1)
31x+77=15x²+30x+15
15x²+30x+15-31x-77=0
15x²-x-62=0
D=1-4*15*(-62)=3721
x1,2=
x1=
x2=
31x + 77 = 15x^2 + 30x + 15
- 15x^2 + 31x - 30x + 77 - 15 = 0
- 15x^2 + x + 62 = 0
15x^2 - x - 62 = 0
D = b^2 - 4ac = 1 - 4*15*(-62) = 1 + 3720 = 3721 = 61^2
x1 = ( 1 + 61) / 30 = 62 / 30 = 31 / 15 = 2 целых 1/15
x2 = ( 1 - 61) / 30 = - 60 / 30 = - 2